Conformity

Going along with the group.

Asch

Asked to judge obviously unequal line lengths, participants agreed with a unanimous wrong majority in a substantial share of trials, knowing it was wrong.

A single ally who dissents collapses the effect.
People conform both to be right and to be accepted; the two motives differ.

In practice

Meetings where the first speaker anchors everyone are the everyday version. Collecting views independently beforehand is the standard antidote.